1. Field of the Invention
The present invention relates to a fluorescent tube type LED lamp using light emitting diodes (LEDs) as light sources.
2. Related Art
Related art fluorescent tube type LED lamps are configured such that a plurality of LED light sources are arranged on a substrate accommodated in an elongated lamp body.
For example, a related art fluorescent tube type LED lamp includes a substrate and LED light sources arranged on the substrate in a line, and the substrate is supported so as to be rotatable about an axis extending in the longitudinal direction of the substrate, so that the light distribution amount in the widthwise direction of the lamp body can be adjusted (see, e.g., JP2007-122933A).
According to another related art, a plurality of light source substrates are arranged in a line in the longitudinal direction of the lamp body, and LED light sources are arranged on each of the substrates. The adjacent substrates are connected together via respective connectors (see, e.g., JP2010-153384A).
However, according to the related art fluorescent tube type LED lamps, due to the use of multiple LED light sources, the light sources appear in a spotted manner. Thus, continuous light emission as in a fluorescent tube lamp cannot be obtained. Further, because the LEDs have a strong directivity, although sufficient light quantity may be obtained in a region directly below the lamp, there is a lack of light quantity in a region lateral to the lamp. For example, as shown in a broken line in FIG. 4, with respect to 1 being the illuminance at the radiation angle of 0° (directly below the lamp), relative illuminance lowers as the radiation angle becomes wide, and may become 0 at the radiation angle of 90° (directly lateral to the lamp).